﻿using System;

class PrintSequenceNumbers
{
    static void Main(string[] args)
    {
        int a = 0;
        int b = -1;
        for (int i = 1; i <= 5; i++)
        {
            a = a + 2;
            b = b - 2;
            Console.WriteLine(a);
            Console.WriteLine(b);
        }
    }
}

